It is a well-recognized fact that car manufacturing procedures call for the addition of an electric system powering battery to each car during the final stages of the electric system installation process and assembly of the electric loads connected therein.
The various electric loads, such as lights, actuators, and the like, are usually driven between a positive supply pole and ground via an electronic control circuit.
Since it is not unlikely for the cables to be occasionally misled which interconnect the supply to such circuits, there exists a demand for an ability to still have the supply battery installed even where polarity has been reversed without this endangering said integrated circuits.
This need also arises, from the likelihood that just the battery connections are reversed by mistake, and becomes specially acute where an integrated circuit includes power actuators including, inter alia, inherent transistors, for which no limiting resistive components can be provided in the supply line since these would lower the supply voltage in consequence of the voltage drop thereacross.
To meet the above demand, it has been proposed that a unidirectional component, specifically a diode, be connected between the positive supply pole and the electronic control circuit to protect such an integrated circuit in the event that the battery polarity is reversed.
While being advantageous cost-wise, this prior approach has a drawback in that the voltage drop Vd across the diode lowers the voltage available to the electric load to be driven, and that the overall efficiency of the system deteriorates due to the power requirements being increased by an amount equal to the product of the voltage Vd across the diode multiplied by the current IL flowing through the load.